Standby mode is a power saving mode for electronic devices that saves electrical power consumption when the electronic device is idle. Standby mode places the electronic device into a state of “waiting for a power-up command”.
In a TV channel selection terminal, commonly referred to as a decoder or set top box (STB), putting the STB into standby mode results in deactivation of the decoder inputs and outputs.
Standby modes in some decoders (such as those deployed by CanalSat, Sogecable and Astro) also result in the stopping of the decoder's onboard software and the turning off/shutting down of most of the decoder's hardware components, including the decoder's random access memory (RAM) memory.
U.S. Pat. No. 5,021,983 describes a method and apparatus for suspending the operation of a computer at any desired point and resuming operation at exactly the same point. At the point where suspension is chosen, the current state of the computer is stored in the computer's Random Access Memory and power is disconnected to all other components in the computer. When resumption of operation is commanded, power is restored to all components and the current computer state is retrieved from the Random Access Memory and restored, allowing operations to continue from exactly the same point as they were suspended.
U.S. Pat. No. 4,646,307 describes an electronic apparatus, for example, a programmable calculator, a portable or handheld computer, a memory module, or a data collector, that incorporates a battery backup RAM, and means for first checking the memory contents when the power-OFF command has been activated, and then causes the results of the checking to be stored in a specific area of the RAM. When the memory contents checking command has been activated, the system rechecks the memory contents to see if the memory contents have varied and can securely confirm whether the memory contents of either the effective programs or data have been correctly backed up when either replacing the battery or during storage of an electronic apparatus that uses the battery backup RAM.
U.S. Pat. No. 6,968,469 describes a CPU that automatically preserves the CPU context in a computer memory that remains powered-up when the CPU is powered down in sleep mode. By means of the preserved CPU context, the CPU is able to instantly and transparently resume program execution at the instruction of the program that was asserted for execution when the CPU was powered down. The CPU is permitted to power down frequently, even during execution of a program, and results in reduced average overall power consumption.
The disclosures of all references mentioned above and throughout the present specification, as well as the disclosures of all references mentioned in those references, are hereby incorporated herein by reference.